hello,
This patch adds a new interceptor for our shell packages.
Right now we cannot load an svg if the image is inside the /contents/images of the shell package.
So this patch solves that issue.

Testing Done

*Testing*
org.kde.desktop shell package works without any issue.
*Issues*
The interceptor doesn't return a scheme for the svg component.
PlasmaCore.SvgItem {
svg: PlasmaCore.Svg {
imagePath: "shellpackage:/images/bar.svgz"
}
}
On the above code, the "path.scheme()" from the interceptor never returns
"shellpackage", so it is completely ignored.
But the following one it works
Image {
source: "shellpackage:/images/foo.png"
}